Magnesium is well known as an injectable for molten metals, in some cases as an alloying agent, or as a deoxidizer, or as a desulfurizer, or in some cases as a nodularizer. Aluminum has also been used as an injectable for molten metals, especially as an aid for a calcium compound, e.g. lime, which is used as a desulfurizing agent for molten iron. Calcium metal may be used in place of the magnesium metal, but it is not cost-competitive with Mg or Al.
It is known that Mg powder or Al powder can be used along with a calcium compound, e.g. lime, by being injected into molten iron either as a physical mixture with a particulate Ca compound or by staged successive injections of the Mg or Al with the Ca compound.
U.S. Pat. No. 4,137,072 discloses a molded pellet form of a mixture of at least one metal selected from Mg, Ca, and Al and at least one metal oxide selected from MgO, CaO, and Al.sub.2 O.sub.3. Preference for Mg+MgO is shown. The use of an organic polymer binding material as an optional ingredient in the mixture is disclosed.
U.S. Pat. No. 4,139,369 discloses a mixture of Mg powder with CaO, CaCO.sub.3, CaC.sub.2, or CaMg(CO.sub.3).sub.2, wherein the Ca compound has a particle size of 0.06 to 3 mm and the Mg particles have a size of 0.060 to 0.095 mm.
U.S. Pat. No. 4,173,466 discloses compacted tablets of particulate magnesium, calcium, and iron in which the iron is the predominant ingredient.
U.S. Pat. No. 4,182,626 discloses a staged mixing process for combining pulverulent Mg metal with fine particle alkaline earth metal compounds.
U.S. Pat. No. 4,209,325 discloses a mixture of alkaline earth metal with sintered lime which contains at least one fluxing agent, said fluxing agent being, e.g. alumina, alkali metal fluoride, alkaline earth metal fluoride, or sodium carbonate.
U.S. Pat. No. 4,586,955 discloses the use of Al metal powder with lime to desulfurize hot metal in a ladle.
U.S. Pat. Nos. 4,559,084 and 4,421,551 disclose salt-coated Mg granules for use in desulfurizing molten iron.
Despite the general successes in using Mg or Al particles along with such things as CaO and CaC.sub.2 as injectables in molten process metal, e.g. molten iron, there remains a need in the industry for an injectable reagent which does not create excessive, unwanted splashing of the molten process metal as the injectables are undergoing reaction therein, is uniform in composition, is more easily and safely handled, and is non-segregating during shipping, storage, and handling.